1. Field of the Invention
The invention relates to the preparation of organic sulfide compounds having improved copper strip corrosion activity.
2. Discussion of the Prior Art
Various proposals have been made for producing organic sulfides by treating olefins with sulfur chlorides and then reacting the resulting intermediate with compounds containing sulfur. For example, organic polysulfides may be prepared by the sulfochlorination of olefins containing 6 or more carbon atoms and further treatment with inorganic high polysulfides according to Eby U.S. Pat. No. 2,708,199. In addition, Meyers U.S. Pat. No. 3,471,404 discloses that sulfurization reactions of this nature may be carried out by reacting a sulfochlorinated isobutylene intermediate produce with a mixture of an alkali metal sulfide and free sulfur in a molar ratio of at least 2:1 followed by a further prolonged treatment with aqueous sodium hydroxide, apparently for reducing high chlorine contents, in producing extreme pressure additives. Beretvas et al. U.S. Pat. No. 3,068,218 indicates that sulfochlorinated products of improved color may be obtained by sulfochlorinating polymers of propylene, etc. containing 8 or more carbon atoms in a aqueous reaction mixture and then sulfurizing the intermediate with a solution of sodium sulfide in water and isopropanol in producing products with sulfur contents of the order of 10 to 34 % by weight. In Kimball U.S. Pat. No. 2,249,312, the sulfochlorinated adduct of amylene or higher olefins is treated with sodium sulfide and/or other alkaline compounds to produce stable products of relatively low sulfur content and generally high chlorine contents.
In general, prior art organic sulfide compounds have one or more of such undesirable characteristics as high cost, low sulfur content, high chlorine content and corrosive attack on metals and alloys used in machinery. Products having a chlorine content above 2% and also those produced from sodium polysulfide reactants are usually rather corrosive. Some of these disadvantages can be overcome and organic sulfide compounds having improved properties, especially as to high sulfur content and more desirable corrosion characteristics, are obtained by the economical process described in U.S. Pat. No. 3,703,504. In this process, the aqueous alkali metal monosulfide reactant employed in the final reaction is derived from a spent effluent stream resulting from hydrocarbon purification operations.